node.js - Realtime authentication in nodejs? -

so learning nodejs , having few problems workflow in node. want build register system starters , when user typing username, want check input on server side if username exists in database.

i'm thinking trick, not sure if way real-time authentication.

on index page have input name , id of "username" and:

<script type="text/javascript">         $('#username').on('keyup', function(e){  var parameter = { parameter: $(this).val() };    $.get( '/validate',parameter, function(data) {       console.log(data);  });   }); </script> 

so idea use onkeyup function , use $.get function send request.

var express = require('express'); var router = express.router(); router.get('/', function(req, res) {   res.render('index'); });  router.get('/validate', function(req, res) {      var val=req.query.parameter;     if (val!=undefined){         var query=req.connection.query("select * registeredusers username="+req.connection.escape(val),function(err,result){             if(err){                 console.error(err);                 return;             }             console.log(query.sql);             var num=result.length;             console.log(num);             if(num==1){                  res.send('username exists ');                                    }           });     } }); 

in past worked lot php , used ajax, im not sure if should still use ajax, questions are: correct way real-time authentication or there better way? can point me correct direction sharing me code of how things should in register system?

x_maras has sad. if use ajax send requests. suggest program postman test api , make request there. here little snipped. have keep wording "parameter" recommend use id or userid or etc

router.get('/register', function(req, res) {     var val = req.body.parameter // if send parameter in body     var val = req.params.parameter // if send url parameter     if (val !== undefined){         return res.send("no parameter provided")     }     var user = ... // here database stuff     if(err){           console.error(err)         return res.send("error")     }     if(!user){         // register user     }      res.send({user: user}) })